def test_len():
n = 10
elements = get_elements(n)
dis = DisjointSet(elements)
assert len(dis) == n
dis.add("dummy")
assert len(dis) == n + 1
def test_add(n):
elements = get_elements(n)
dis1 = DisjointSet(elements)
dis2 = DisjointSet()
for i, x in enumerate(elements):
dis2.add(x)
assert len(dis2) == i + 1
# test idempotency by adding element again
dis2.add(x)
assert len(dis2) == i + 1
assert list(dis1) == list(dis2)